If we assume that 50% of them are plugged in, that's an additional 100MW of generating capacity needed worldwide.
From a Houston Chronicle aritcle, http://blogs.chron.com/sciguy/archives/2006/06/coa l_affordable_1.html
, an 1000MW coal plant spews 6 million tons of carbon dioxide into the atmosphere per year.
So, a 100MW coal plant would spew 600,000 tons of CO2 per year
That's the impact. But, this is only for 2W standby power for one product.
... $2.63 * 50 million = $131.5 million. That's like 1000 houses for 1000 homeless families
... and that's in the United States
... that money could go further in other places.